:root {
  color-scheme: light dark;
  --bg: #f6f7f9;
  --fg: #1a1d21;
  --muted: #5a6270;
  --card-bg: #ffffff;
  --card-border: #e3e6eb;
  --accent: #1f5fd8;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101317;
    --fg: #f1f2f4;
    --muted: #9aa3af;
    --card-bg: #1a1e24;
    --card-border: #2a2f37;
    --accent: #6ea1ff;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP",
    "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 12vh 20px 40px;
}

header {
  text-align: center;
  margin-bottom: 40px;
}

.logo {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  margin-bottom: 16px;
}

h1 {
  font-size: 1.6rem;
  margin: 0 0 8px;
  letter-spacing: 0.02em;
}

header p {
  color: var(--muted);
  margin: 0;
  font-size: 0.95rem;
}

main {
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.card {
  display: block;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  padding: 18px 20px;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.card-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 0 0 4px;
  color: var(--accent);
}

.card-desc {
  margin: 0;
  font-size: 0.88rem;
  color: var(--muted);
}

footer {
  margin-top: 48px;
  font-size: 0.78rem;
  color: var(--muted);
}